Track drives have been used for years in many types of vehicles. Battle tanks, bulldozers and snow machines all use some type of track drive. One type of vehicle typically known as a "snow cat" is a medium sized vehicle used during winter conditions. These vehicles have track drive and are designed to travel on snow. The suspension systems found on these vehicles limits the speed to about 18 miles per hour. So, although these vehicles are useful, they are slow. Examples of such track vehicles are found in U.S. Pat. Nos. 1,368,652 to Pennington et al., 1,329,316 to Wickersham, and 3,148,743 to Jarvi et al.
One type of snow vehicle that can attain high speeds is the snowmobile or snow machine. These vehicles use single or multiple tracks, each mounted inside a frame or "tunnel". The track uses a sliding rail type suspension system (sometimes called a skid type suspension) that allows these vehicles to operate at speeds of 50 to 80 miles per hour or more. Examples of this type of suspension system are found in U.S. Pat. Nos. 3,701,394 to Hendrickson, 3,744,583 to Bedard and 4,222,453 to Fixsen et al. Common to all these suspension systems is that each track is supported on both of its sides by the frame or tunnel. None of these systems can be used on a two track vehicle that has each track mounted on the outside of the vehicle, as there is no frame or tunnel to support the outboard mounting of the suspension system. As a result, track vehicles have used a different type of suspension that limits the speed and even the functionality of the vehicle.
The original design of this invention is a track vehicle that uses a sliding rail type suspension, which is mounted on the outside of the vehicle frame. A supporting frame member, which is attached to the outside of both tracks, is used to support the outer edge of the tracks. The use of the sliding rail type of suspension allows the vehicle to operate at high speeds. The use of a cross member support allows the sliding rail suspension to be used on the outside of the frame. A special brace member passes through each track and attaches to the outer edge of the track suspension. This member braces the tracks and allows them to operate as if they were mounted between frame members, as in a snow machine. The bracing member is lightweight and is designed to enable easy and fast track removal.